The goal of this project is to identify and serologically analyze human lymphocyte differentiation antigens on the surfaces of two human lymphoblastoid cell lines. These antigens will be related to antigens found on mature, developing, and neoplastic lymphoid cells from fresh human tissues. The cultured lines to be used are RPMI 8392 and RPMI 8402 cells. These lines were established from the same leukemic individual. One line (8392) is a B cell line, while the other probably arose from the tumor stemline. We plan to use immunofluorescence as a major tool in the analysis of antigens on these cells. The availability of a fluorescence-activated cell analyzer and sorter (Beckon-Dickinson FACS-III) will facilitate a quantitative analysis of the data. The goals set for the current year include the preparation of high-titer antiserums to these two cells lines. A blocking procedure was used to suppress antibody responses to antigens found on both cell lines.